AC_Fence: fixed 2 regressions from 4.5.x #44602

Job	Run time
build (stm32f7, chibios, 10)	3m 38s
build (stm32h7, chibios, 10)	3m 20s
build (fmuv2-plane, chibios, 10)	2m 7s
build (periph-build, chibios, 10)	3m 46s
build (iofirmware, chibios, 10)	1m 30s
build (CubeOrange-bootloader, chibios, 10)	53s
build (fmuv3-bootloader, chibios, 10)	49s
build (revo-bootloader, chibios, 10)	1m 4s
build (stm32h7-debug, chibios, 10)	2m 5s
build (fmuv3, chibios, 10)	5m 49s
build (revo-mini, chibios, 10)	4m 13s
build (MatekF405-Wing, chibios, 10)	4m 41s
build (CubeOrange-ODID, chibios, 10)	2m 38s
build (CubeRedPrimary-bootloader, chibios, 10)	1m 3s
build (configure-all, chibios, 10)	10m 53s
build (build-options-defaults-test, chibios, 10)	6m 50s
build (signing, chibios, 10)	2m 46s
build (CubeOrange-PPP, chibios, 10)	2m 14s
build (CubeRed-EKF2, chibios, 10)	1m 59s
build (SOHW, chibios, 10)	3m 32s
build (Pixhawk6X-PPPGW, chibios, 10)	1m 27s
build (new-check, chibios, 10)	4m 14s
	1h 11m 31s

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